Chris Christie, the Republican nominee in this year's race for governor of New Jersey, apparently has determined not to make property taxes a central issue of the campaign against Democratic incumbent Jon Corzine and instead to focus on corruption. And this is proving to be a costly decision.

"That decision could be the one that ends up sinking [Christie's] campaign," says Patrick Murray, director of Monmouth University's polling institute.

I say "apparently" in describing Christie's strategy because, while it is beyond dispute that his campaign has failed to make property taxes a central issue of its platform so far, it is not necessarily true that the campaign has no plans to make tax reform the focal point of the fall campaign.

It is at least possible that the Christie campaign has made a decision to hunker down through the hot summer months, when only a relatively small segment of New Jersey voters are paying attention, and instead save its ammunition for a concentrated burst in the final weeks of the campaign.

Will someone please pass this message to the people running the Republican Governors Association: "Please, sirs, stop running the inane negative spots attacking Jon Corzine, and instead start running positive spots building up Chris Christie?! Or, at the very least, if you insist on running attack spots, could you at least run attack spots that might actually have a chance of working?"

I've written before about the strategic imperative facing Republicans who want to win this year's contest for New Jersey governor: To do so, they first must win the war over GOP nominee Chris Christie's image.

Virtually every likely voter in the state knows and has an opinion about Corzine, the incumbent Democrat -- according to the latest survey from the Quinnipiac University Polling Institute, for example, only 6 percent of the survey sample said they hadn't heard enough about Corzine to form an opinion.

Well, the new survey from the Quinnipiac University Polling Institute is out, and the race for New Jersey governor is tightening: GOP challenger Chris Christie clings to a 6-point, 46 percent to 40 percent lead over incumbent Democratic Gov. Jon Corzine, with independent candidate Chris Daggett drawing 7 percent of the vote.

That's a significant movement from the July 14 survey, which showed Christie leading Corzine by 47 percent to 38 percent, with Daggett at 8 percent.

"Significant movement" when it's just a 3 point difference? Yes, it's significant, when 3 points is the difference between a 9-point lead and a 6-point lead. In that difference, the 3 points represents a 33 percent cut -- so Corzine's team can say, "We've cut Christie's lead by a third."

Plus, in a poll where the margin of error is plus or minus 2.9 percent, that 6-point lead begins to look even smaller -- because it might just be a 3-point lead, and there's still 12 weeks to go.

Check out New Jersey Gov. Jon Corzine's latest television spot.

Is it just me, or does this leave you with the impression that the incumbent has caved to pressure from powerful Democratic Party bosses, and announced his decision to let Barack Obama run at the top of the ticket with Corzine as lieutenant governor?

This ad is notable for four things:

1) It's Corzine's first positive ad of the campaign season.